Guide wires are used in various procedures within various conduits in the body. In particular, they are used in Percutaneous Transluminal Coronary Angioplasty (PCTA) and other coronary procedures. This can involve inserting a guide wire through an incision in the femoral artery near the groin, advancing the guide wire over the aortic arch, into a coronary artery, and across a lesion to be treated. Guide wires can be inserted directly into the vasculature or within a guide catheter. The distal end of the guide wire ultimately lies directly within the vasculature.
Guide wires serve to guide devices into position for both therapeutic and diagnostic purposes. For this to happen, the guide wire itself must be properly positioned. This is difficult, as it involves moving a wire tip through a narrow opening within a narrow vessel, from 180 centimeters away. This task can be especially difficult as the guide wire must be extremely flexible at the distal end to enable the guide wire tip to enter vessel branches at various angles. The extreme flexibility can come at the expense of axial or rotational strength. Improved responsiveness to remotely applied forces, both rotational and axial, has been provided by reducing friction along the guide wire length. In particular, providing a highly lubricous guide wire distal region of about 12 inches has proven advantageous in maneuvering guide wires through the arteries to reach the site of blockage. Having this same lubricous coating on the tip of the wire has been advantageous in making the wire perform better in finding small openings in the blockages and crossing them.
Once the guide wire tip is in position, devices including catheters are advanced into position over the guide wire and withdrawn over the guide wire. Such catheter movement acts upon, and tends to move, the guide wire contained within. This can tend to dislodge the guide wire tip. Minor patient movement including breathing also acts to move the guide wire as does handling of the guide wire proximal portion extending from the patient. Dislodging the guide wire tip may require repositioning the guide wire, with the attendant time and effort. Once in position, therefore, stability and resistance to applied forces is preferred over the initially desirable ease of movement and responsiveness to applied forces.
What is desirable and has not been provided is a guide wire easily maneuvered into position across a tight lesion, yet providing stability and resistance to movement once the guide wire is in position.